The buspirone challenge test clearly distinguishes ME/CFS patients from healthy controls: why is it not being developed and deployed?

[Hip]

I think this is one of the issues at work with ME biological abnormalities. If its not shown to be diagnostic then clinicians tend to ignore it.

Sure, the ideal test would actually measure some biological parameter which is at the core of ME/CFS pathophysiology, and hopefully a parameter unique to ME/CFS. Though as we are not currently sure what the core pathophysiology of ME/CFS is, that makes it difficult to develop such a test.

 

[Alvin]

I have never come across anyone with ME/CFS being misdiagnosed with indigestion or social anxiety, which bear little symptomatic resemblance to ME/CFS.

Are you kidding?
People have been misdiagnosed with more things instead of ME then we could shake a stick at.
I bet if anyone collected a list it would be Yuge!

 

[Hip]

People have been misdiagnosed with more things instead of ME then we could shake a stick at.

Yes, the lists of symptomatically similar diseases to ME/CFS are quite long, but I have not seen any lists that contain dyspepsia or social anxiety (= anxiety about how other people judge or evaluate you).

 

[Alvin]

Yes, the lists of symptomatically similar diseases to ME/CFS are quite long, but I have not seen any lists that contain dyspepsia or social anxiety (= anxiety about how other people judge or evaluate you).

[Patient] has social anxiety hence you want to avoid future situations so your brain tells you your tired as a way to avoid them.
The fact it happens in other situations that involve physical activity means you need a lifetime of Freudian "therapy"
Or it just might mean [Patient] has hysteria and this was the trigger...

Framing complex problems in similar terms to these is not at all rare. I got lucky that i had a doctor who at his retirement and years of testing to no avail told me i don't know whats wrong with you instead of your obviously neurotic...

 

[Hutan]

[Patient] has social anxiety hence you want to avoid future situations so your brain tells you your tired as a way to avoid them.

Yes, I'm sure that assumption is common. My son was diagnosed with conversion disorder (fear of school) by a psychologist - (although there was nothing in his history to suggest that he had problems with school - quite the opposite).

I think these facts make it useless as a test for us. It all too easily allows doctors to simply re-diagnose us with social anxiety and/or dyspepsia - treatment - CBT.

It's certainly a risk with any research that involves neurological transmitters that the BPS crowd grab hold of it and twist it to their own ends. I feel uneasy anytime serotonin or dopamine is mentioned in connection with ME. It doesn't mean that leads shouldn't be followed though.

To me, the primary benefit of looking in to this buspirone challenge at this stage is that it might, just possibly, tell us something the about disease mechanism, rather than it being a diagnostic test.

 

[Hip]

To me, the primary benefit of looking in to this buspirone challenge at this stage is that it might, just possibly, tell us something the about disease mechanism, rather than it being a diagnostic test.

I think so too. It's unfortunate that there are two alternative theories to explain the mechanism of the buspirone-stimulated prolactin release, so although we know that there is exaggerated release in ME/CFS, we cannot be sure of the mechanism.

The original theory is that there may be an increased sensitivity or up-regulation of the serotonin receptors in the hypothalamus in ME/CFS, and so when buspirone — a serotonin 5-HT1A agonist — is given to ME/CFS patients, it produces a larger than normal stimulation in the hypothalamus. If true, this assumed increased hypothalamic serotonin receptor sensitivity might shine some light on the HPA-axis dysfunction in ME/CFS.

The alternative theory proposed by Sharpe et al is that the increased prolactin response to buspirone in ME/CFS might reflect changes in the dopamine system, as buspirone is also a dopamine D2 receptor antagonist, and these D2 receptors are also involved in prolactin secretion. That may also shine some light on the HPA-axis dysfunction, but a dopaminergic rather than serotonergic light.

 

[Snow Leopard]

For any marker to be used as a diagnostic test it needs to have very high sensitivity and specificity, demonstrated by replication studies comparing to other illnesses as well as healthy controls. As far as I know, no numbers of sensitivity/specificity have been published for the buspirone challenge, so it's use as a test is speculative at best.

My personal opinion is that it will have poor sensitivity/specificity, but I'm willing to be proven wrong.

 

[Little Bluestem]

It all too easily allows doctors to simply re-diagnose us with social anxiety and/or dyspepsia - treatment - CBT.

CBT for dyspepsia?

 

[Hip]

For any marker to be used as a diagnostic test it needs to have very high sensitivity and specificity, demonstrated by replication studies comparing to other illnesses as well as healthy controls. As far as I know, no numbers of sensitivity/specificity have been published for the buspirone challenge, so it's use as a test is speculative at best.

The Richardson study on 30 ME/CFS patients and 30 controls gives some information on this:

In the patients, the mean figure for the prolactin ratio is 3 times higher than that in the controls, a highly significant difference. A ratio 2.5 and upwards encompasses 26 out of 30 patients and a ratio of less than this defines a similar proportion of controls, assuring a reliability for the distinction of 87%.

The ratio here refers to the person's buspirone-stimulated blood prolactin level, divided by the mean buspirone-stimulated prolactin level of the healthy controls. Judging by Figure 2 in the study the mean level of the controls is 400 mIU/L, meaning the threshold level for ME/CFS diagnosis would be 2.5 x 400 = 1000 mIU/L = 47 ng/mL (conversion to different units of measurement given here).

So it looks like in this small-scale study at least, the buspirone challenge test sensitivity and specificity are both 87% if you set the threshold for positive diagnosis at a ratio of 2.5.

As a reminder: Sensitivity is the proportion of people with disease who have a positive test result. Specificity is the proportion of people without disease who have a negative test result.

It's possible one might be able to improve this sensitivity and specificity even further if you also take into account the time-to-peak data that was measured in the Sharpe study (this study found not only higher prolactin peaks in ME/CFS patients after buspirone stimulation, but also a faster time-to-peak).

 

[Manganus]

They can prescribe all they want, i'm not going t o take any of them, my sleep abnormalities are clearly ME related, as the ME gets wore the circadian rhythm gets worse in lockstep. Either its the coincidence of the millennium or A is causing B.

Seconded!

 

[Hip]

I came across this UK finger prick home blood test for prolactin levels for £39, which means you could test yourself.

The only thing is that I understand finger prick home blood tests are not that accurate, as finger prick blood samples are too small. But the same test also has an option to supply the blood by normal venipuncture (for an additional charge), which will have the normal accuracy.

 

[Trish]

Given that buspirone is, as far as I know, a prescription medication, I can't imagine a responsible doctor prescribing it so a patient can do an unproven and inaccurate home test that might or might not show they have ME or some other condition that causes raised prolactin...

So I assume your suggestion is not a serious one.

 

[Hip]

Given that buspirone is, as far as I know, a prescription medication, I can't imagine a responsible doctor prescribing it so a patient can do an unproven and inaccurate home test that might or might not show they have ME or some other condition that causes raised prolactin...

So I assume your suggestion is not a serious one.

You assume wrongly. It is a serious idea.

In the UK it is legal to import any non-controlled prescription medication for personal use, so you don't need to involve your doctor if he is unwilling.

 

[Hutan]

Moderator note: members are reminded that prescription medicines are designated as such for safety reasons and may have side effects that are significant for some people.

 

[Alvin]

You assume wrongly. It is a serious idea.

In the UK it is legal to import any non-controlled prescription medication for personal use, so you don't need to involve your doctor if he is unwilling.

Moderator note: members are reminded that prescription medicines are designated as such for safety reasons and may have side effects that are significant for some people.

@Hip I get that your enthusiastic about this but this is not a smart thing to play with especially when something like the Canadian Consensus Criteria work quite well. Not to mention Dr Leonard Jason's high specificity questionnaires which i would love to see verified since he claims they work well even in early stages of mild ME.
If this is about smashing the PACErs it won't work because they have no interest in facts, as we see in politics reality means nothing to ideologues. To them its about belief and anything that contradicts their beliefs will be dismissed. Sophistry is a well sharpened sword in todays world.

 

[Snow Leopard]

The Richardson study on 30 ME/CFS patients and 30 controls gives some information on this:

The ratio here refers to the person's buspirone-stimulated blood prolactin level, divided by the mean buspirone-stimulated prolactin level of the healthy controls. Judging by Figure 2 in the study the mean level of the controls is 400 mIU/L, meaning the threshold level for ME/CFS diagnosis would be 2.5 x 400 = 1000 mIU/L = 47 ng/mL (conversion to different units of measurement given here).

So it looks like in this small-scale study at least, the buspirone challenge test sensitivity and specificity are both 87% if you set the threshold for positive diagnosis at a ratio of 2.5.

87% is very poor for a cherry picked/post-hoc threshold.

 

[Hip]

@Hip I get that your enthusiastic about this but this is not a smart thing to play with especially when something like the Canadian Consensus Criteria work quite well.

Yes, the CCC do work quite well, but we have all seen the cases of patients who were misdiagnosed with ME/CFS for years when they actually had a much more treatable illness.

I remember one patient on Phoenix Rising who though she had ME/CFS, but it eventually turned out to be growth hormone deficiency, and GH treatment fixed all her symptoms. More recently a patient on Health Rising, who for 10 years thought he had ME/CFS, later realized it was CIRS (biotoxin illness), and again the right treatment got him back to near full health in just 5 months. And another recent patient on PR, who it turns out had craniocervical instability causing all the symptoms of ME/CFS including PEM, once he got the correct diagnosis and had surgery, that fixed all his symptoms.

These patients probably met the CCC, but did not have ME/CFS, and wasted years chasing the wrong disease and the wrong treatments.

So there is a need for a ME/CFS blood test, and I am wondering why this one, which is cheap and simple, was not further developed.

87% is very poor for a cherry picked/post-hoc threshold.

Maybe, but since research seems to have stopped on the buspirone challenge test, so we will never know what sensitivity and specificity might be possible.

 

[Luther Blissett]

I've known of people with ME to have been diagnosed with general anxiety disorder, social anxiety and agoraphobia. There is also the problem that it is hard to separate social anxiety from agoraphobia, and sometimes it is both. I would not be surprised if a feeling of not having the backing of the medical system, or past mistreatment can contribute to them being co-morbid in ME patients.

When the fear avoidance model is used as an explanation for ME, illnesses with fear avoidance can look like ME and vice versa. It's no co-incidence that the behavioural treatments are very very similar, including CBT and GET.

 

[Alvin]

Yes, the CCC do work quite well, but we have all seen the cases of patients who were misdiagnosed with ME/CFS for years when they actually had a much more treatable illness.

I remember one patient on Phoenix Rising who though she had ME/CFS, but it eventually turned out to be growth hormone deficiency, and GH treatment fixed all her symptoms. More recently a patient on Health Rising, who for 10 years thought he had ME/CFS, later realized it was CIRS (biotoxin illness), and again the right treatment got him back to near full health in just 5 months. And another recent patient on PR, who it turns out had craniocervical instability causing all the symptoms of ME/CFS including PEM, once he got the correct diagnosis and had surgery, that fixed all his symptoms.

These patients probably met the CCC, but did not have ME/CFS, and wasted years chasing the wrong disease and the wrong treatments.

So there is a need for a ME/CFS blood test, and I am wondering why this one, which is cheap and simple, was not further developed.

I will not argue that having a disease thats diagnosed by exclusion will lead to misdiagnosis because it will which is what i hate about conclusion by exclusion. But we do not know whether or not those other patients met the CCC. That said i don't think this is the test that is going to weed out all other diseases. I would consider the nanoeedle to be a better candidate though it even needs to be validated (and the molecule causing the signal identified).

 

[adambeyoncelowe]

It's also important to remember that Sharpe's patients fulfilled CFS criteria but also criteria for neurasthenia. I'm not sure what the latter means, or whether it affects those results (e.g., by selecting for patients with obvious nervous/anxious symptoms which might skew the response).